题目

我国实行无偿献血制度，健康成年公民参加无偿献血，能为挽救他人的生命奉献爱心．健康成年人每次献血多少不会影响健康（ ） A．1200﹣1500mlB．200﹣300mlC．800﹣1000mlmlD．超过400ml 答案：B What were you doing ________ nine and eleven yesterday? [　　] A．from B．at C．among D．between